1. Technical Field
The present disclosure relates to a fuel cell system.
2. Description of the Related Art
A fuel cell system takes out chemical energy as electrical energy by supplying hydrogen containing gas and oxygen containing gas (air) to a fuel cell and promoting electrochemical reaction between the hydrogen and the oxygen. The fuel cell system is a high-efficiency electric power generation system, which can easily utilize thermal energy caused in electric power generation operation, and is accordingly a dispersive electric power generation system with high efficiency of energy utilization.
For example, such a fuel cell system includes an air supplier that supplies air to a cathode of a fuel cell, such as a pump, a reformer that supplies hydrogen to an anode of the fuel cell, an electric power conversion device (an inverter) that converts electrical energy caused in the fuel cell into commercial voltage frequencies, a heat recovery device that recovers heat caused in the fuel cell and the reformer through heat exchange, a blower that ventilates the inside of a casing (a package), such as a ventilating fan, and a radiator that is used for cooling when no exhaust heat is utilized.
When the above-described fuel cell system is used as a household electric power generator, the fuel cell system is typically placed outdoors because of the need for ensuring placement space for the fuel cell system. To cover part or all of the electric power used at home, all-day operation is performed in many cases. Thus, when noise is caused during operation of the fuel cell system, displeasure is given not only to the user but also to the neighborhood. Decrease in the noise of the fuel cell system is therefore necessary so as not to give such displeasure to the user or the neighborhood during daytime as a matter of course, and in particular, during nighttime.
Most of the noise that originates from the fuel cell system is caused by the air supplier, which is a constituent device of the fuel cell system. Noise occurs as suction sound, vibrations caused during operation, and the like of the air supplier propagate to the piping, exterior, and the like of the system. Thus, various methods are reviewed so as to inhibit the sound from the air supplier, which is the noise source of the fuel cell system.
Examples of the configurations that have been proposed include a configuration where a noise blocking wall is attached to the exterior of a fuel cell system (see for example, Japanese Unexamined Patent Application Publication No. 2008-84564), a configuration where a silencer is attached to an air inlet (see for example, Japanese Examined Utility Model Registration Application Publication No. 3-13593), and a configuration where noise that escapes from the exterior of a fuel cell system is reduced by making the cross-sectional area of a passage of an air inlet small (see for example, Japanese Patent No. 5560665).
Further, a configuration where for example, a resonance silencer is provided in a position in a passage through which air flows has been proposed (see for example, Japanese Unexamined Patent Application Publication No. 2005-116353, Japanese Unexamined Patent Application Publication No. 2011-113697, and Japanese Unexamined Patent Application Publication No. 2015-153569).
However, Japanese Unexamined Patent Application Publication No. 2008-84564 and Japanese Examined Utility Model Registration Application Publication No. 3-13593 each have an issue that increase in size and cost of a device is incurred. Japanese Patent No. 5560665 has an issue that pressure loss of an air passage increases. Japanese Unexamined Patent Application Publication No. 2005-116353, Japanese Unexamined Patent Application Publication No. 2011-113697, and Japanese Unexamined Patent Application Publication No. 2015-153569 lack sufficient review of an issue brought by pressure pulsation of air, which is caused by an air supplier. Such issues are described in detail in an embodiment below.